Generally, traditional electronic cigarettes are supplied powers from rechargeable batteries. The rechargeable batteries need to be recharged when they are run out of powers since the powers stored in the rechargeable batteries are limited. USB chargers are widely used resulted from the advantages in carrying and utilization.
However, traditional USB chargers don't have batteries built in, so they can only charge the battery rod in the electronic cigarette via connecting external power sources. If a user is traveling outdoors, in which case lacking of power source, the electronic cigarette can't be charged. Therefore, the user can't use the electronic cigarette conveniently, which can't meet the user's demand.